Advanced Work ow Patterns

Conventional work ow functionality like task sequencing, split parallelism, join synchronisation and iteration have proven e ective for business process automation and have widespread support in current work ow products. One the other hand, newer requirements for work ows are encountered in practice, opening grave uncertainties about the extensions for current languages. Di erent concepts, although outwardly appearing to be more or less the same, are based on di erent paradigms, have fundamentally di erent semantics and di erent levels of applicability more specialized for modelling or more generalized for work ow engine posit. By way of developmental insight of new requirements, we de ne work ow patterns which are described imperatively but independently of current work ow languages. Through a detailed insight into a number of commercially available work ow management systems we highlight the semantic di culties and implementations in the current state of the art.